Conventionally, each of screen states at plural times on a time line, which are reference points of an animation, is defined as a key frame. A screen state means the display positions and display states of parts (objects) which construct the screen. A conventional animation editing device creates an animation by defining a method of interpolating the display positions and display states of parts which vary with time between key frames (parts arranged in each key frame).
Furthermore, patent reference 1 discloses an animation editing technology of specially bringing each key frame into correspondence with a symbol showing time abstractly without directly bringing each key frame into correspondence with time, thereby separating the editing of each key frame from the editing of the time to improve the efficiency of the animation editing process.    [Patent reference 1] JP,2007-122265,A (see pages 3 to 4)
However, in the conventional animation editing device, both a change in the display position of each part and a change in the display state of each part are defined with reference to the display time on the time line. Therefore, when an editor desires to change the display state (the display color or the like) of a part according to the display position of the part, the editor needs to bring a desired display position and a desired display state into correspondence with an identical time on the time line, and has to carryout editing of key frames and editing of times simultaneously. A problem is therefore that the editing process becomes complicated.
Furthermore, in the conventional animation editing process, in order for the editor to check the display position and display state of each part in the animation created during the editing process, the editor needs to cause the conventional animation editing device to display the key frames one by one. A problem is therefore that the conventional animation editing device is inferior in at-a-glance visibility. This problem similarly arises in the animation editing technology according to the invention disclosed by patent reference 1 of showing a time with an abstract symbol, thereby improving the efficiency of the editing process.
The present invention is made in order to solve the above-mentioned problems, and it is therefore an object of the present invention to provide an animation editing device which enables an editor to edit an animation while easily bringing part positions on the screen into correspondence with the display states of the parts at the positions and enables the part positions on the screen into correspondence with the display states of the parts at the positions and enables the editor to easily understand the correspondence between the positions and the display states also from the edit results, an animation playback device which plays back the animation, and an animation editing method.